The natural membrane separation mechanism in plants is inspiring the development of new industrial technologies for application in wastewater recycling and extracting value from waste.
Led by scientists from The Australian National University (ANU), the study deep-dives into how plants obtain water and nutrients from the surrounding soil, and use their membrane separation mechanisms to separate resources from undesirable waste. These mechanisms are now inspiring novel industrial membrane separation technologies, with the knowledge gained from the study being applied to develop precision separation technologies, allowing resources to be harvested from industrial wastes and paving the way to a circular economy.
By adapting plant 'membrane separation mechanisms' for new wastewater recycling technologies, the ANU researchers are looking to offer a sustainable solution to help manage the resources required for the world's food, energy and water security by providing a way to harvest, recycle and reuse valuable metal, mineral and nutrient resources from liquid wastes.
Applicable across agriculture, aquaculture, desalination, battery recycling and mining among others, the technology could also help companies revisit their approach to how they deal with waste by creating a way to extract value from wastewater.
For instance, global wastewater is estimated to contain three million metric tons of phosphorus, 16.6 million metric tons of nitrogen and 6.3 million metric tons of potassium, the recovery of which could offset 13.4 percent of global agricultural demand for these resources. Additionally, the ammonia and hydrogen molecules embedded in wastewater could potentially provide electricity to 158 million households in a world that’s facing an energy crisis.
"The world's wastewater contains a jumbled mess of resources that are incredibly valuable, but only in their pure form. A big challenge researchers face is figuring out how to efficiently extract these valuable minerals, metals and nutrients while retaining their purity," ANU plant scientist associate professor Caitlin Byrt said.
"The Australian mining industry, for example, creates more than 500 million tons of waste per year, and these wastes are rich in resources like copper, lithium and iron. But at the moment the liquid waste is just a problem; it can't be dumped and it can't be used. It's just waste unless each resource can be separated out in a pure form."
Similarly, in the battery recycling space, there is a huge, rich source of lithium inside dead batteries that cannot be extracted or reused efficiently. “Harvesting resources from industrial and urban waste is a key step towards transitioning to a circular green economy and building a sustainable future, as well as reducing our carbon footprint."
In addition to resources such as boron, iron, lithium and phosphorus that are used in battery technologies, the researchers are also exploring the extraction of ammonia – a compound used to create fertiliser – from liquid waste solutions.
"Fertiliser costs are going through the roof, which puts a lot of pressure on Australian farmers to be able to afford these higher prices, and yet we're wasting huge proportions of these molecules and that's causing environmental problems," Byrt says.
Observing that the research has implications for flood- and drought-prone communities across Australia, Byrt explained that precision separation technology could offer security by providing them with portable, secure and reliable access to clean drinking water.
"Clean water and the security of nutrient resources underpin agricultural productivity. Development of technologies to sustainably manage these resources is essential for food security in Australia and globally," she said.
The research is published in New Phytologist.
Image: https://cleanawater.com.au/information-centre/nsw-wastewater-guidelines
